124 Mayow 



for the formation of a flame, it seems to be necessary 

 that the sulphureous particles should neither be too 

 fixed nor very volatile. For we notice that the sul- 

 phureous particles of spirit of wine and also the very 

 subtle particles of camphor, are scarcely able to throw 

 nitro-aerial particles into fiery motion. And this is 

 the reason that the fire they make is but languid and 

 almost harmless. And indeed it is probable that 

 sulphureous particles, in passing through the flame,, 

 are rendered so subtle by their own burning that 

 they become quite unfit to produce fire. And this 

 seems to be confirmed by the fact that if any polished 

 plate be placed in the flame of a lighted candle, we 

 shall soon see it covered with soot ; but if the plate 

 be held a little above th^ flame, no soot will gather on 

 it. For the soot adhering to the plate seems to be 

 nothing else than the sulphureous particles which 

 shortly before were burning ; now indeed they are 

 changed somewhat in consequence of their burning 

 and rendered more subtle and scorched. But those sul- 

 phureous particles which have burned longer, become 

 at last so fine that they are incapable either of con- 

 stituting the grosser structure of soot or of producing 

 flame. It is a confirmation of this that the lower 

 part of any flame is very different from the top. For 

 the lower part is usually blue, while the upper part 

 burns more brightly. And this difference seems to 

 result from the different state of the sulphureous 

 particles. Now then, since the sulphureous particles 

 carried through the flame get smaller during the 

 whole course of their passage and are therefore to 

 some extent consumed, the flame must gradually 

 become smaller and end at last, as it does, in a 

 point. 



